[Cin] User Defined Blend Algebra

[Andrea paz]

I am responding on the mailing list so as not to make the bug tracker
chaotic with my incompetent attempts.

You answered me:
"The EDIT button, if pressed while the text field of the function name
is empty (i.e. no function selected), does nothing. If it is the case
for you, try first to select some function (or enter a name for the
new one), then edit. Perhaps we should show some error message in such
cases, saying that a function should be selected first."

Thanks, I didn't realize to write in “function” before using the “edit” button.
I tried writing “subtract” in Function and then hitting the edit
button and I get the following lines on the terminal:

BlendAlgebraCompile: copying
/home/paz/cinelerra5/cinelerra-5.1/bin/dlfcn/BlendAlgebraCompile.pl to
/home/paz/.bcast6/BlendAlgebraCompile.pl
BlendAlgebraCompile: executing emacs /home/paz/subtract &
sh: line 1: emacs: command not found
export CIN_EDITOR=kate
BlendAlgebraCompile: executing emacs /home/paz/subtract &
sh: line 1: emacs: command not found
BlendAlgebraCompile: executing emacs /home/paz/subtract &
sh: line 1: emacs: command not found

I tried doing an export both inside the open CinGG terminal and from
an external terminal, but the plugin still seems to refer to emacs.

Finally I found the solution (thanks to your answer) to my problems.
I use .bcast6 because .bcast5 I leave for appimage. In the file
“/home/paz/.bcast6/BlendAlgebraCompile.pl” I changed emacs to kate and
.bcast5 to .bcast6.
With these changes the plugin works; it opens kate where I paste your
example code for the subtract and then save and close kate.
I put the plugin in the “top” track, setting “top first” and output in
the top track. I put the plugin as “shared” in the bottom track.
I get the black compositor window. If I set the output as “bottom”
instead the plugin works and I get the blend set. So, if I understand
correctly, the plugin goes into the top track (and shared in bottom)
and needs to be set:

- track order: “top first” or ‘bottom first’ depending on the blend we
want to achieve
- Output track: “bottom” (I do not understand in which cases ‘top’
could be used)
- Hide imput tracks, use output exclusively: active (I do not
understand in which cases to use “off”)

In other cases I get either black screen or unaltered output tracks. I
don't really understand these behaviors and need to do further
testing. Given my lack of expertise, perhaps it is better to use the
functions in the library than to use EDIT?